Derrick Hitchins

1. SIZE DOES MATTER –
BUT WHEN IS BIG TOO BIG?
Derrick Hitchins, SMEC Australia
2016 AITPM National Conference, Sydney, July 2016
1

2. • New vehicle designs offer significant advantages to
commercial freight operators in terms of volume and
payload.
• For this reason it is inevitable that the industry will continue
to call for a change to the rules and regulations that govern
them.
• In response, state road authorities and enforcement
agencies have to continue to modify their standards and
guidelines with respect to the operation of those vehicles
• It is therefore imperative that we as traffic engineers
become more familiar with the needs of this ever-changing
heavy vehicle fleet.
Introduction
2

3. A. How big is Big ?
B. Road Access Arrangements
C. Treatment of high-productivity vehicles in Queensland
D. Understanding the impact of these larger vehicles on our
roads
E. How should traffic engineers and planners respond
Presentation Overview
3

4. General Access Vehicles
A. How big is Big ?
4
• B-double (19m max)
• Do not require a notice or permit to operate on the road
network
• Have general access to the road network unless the road is
sign-posted otherwise

5. Prime mover towing two semi-trailers connected by a drawbar
Type 1 Road Trains (36.5m max)
5
B-triple
AB-triple

6. Type 2 Road Trains (53.5m max)
6
BAB-quad
ABB-quad
Prime mover towing three semitrailers connected by drawbars
Rigid truck towing two semitrailers connected by a drawbar

7. But when is big is too Big ?
7

8. Productivity Benefits Quantified
8Source: Moving Freight: An update on road network freight access

9. Heavy Vehicle National Law (Commonwealth of Australia)
• Governs the use of B-doubles in stated areas, on stated
routes, during stated hours of stated days and under stated
conditions.
• The NHVR liaises directly with road managers to manage
applications and issue permits.
For General Access Vehicles (i.e. < 19m)
• Road managers provide pre-approved consent for a range of
approved heavy vehicle routes
• In turn, Austroads (2009) guidelines for Arterial Roads
requires designers to
– Design for 19m vehicles and check for 25m e.g. B-double
B. Road Access Arrangements
9

10. B-double (23m-25m-27.5m max)
NHVR Class 2 Heavy Vehicles - Notice or permits must issued by
National Heavy Vehicle Regulator (NHVR).
10
A-double (36.5m max)
B-triple (53.5m max)
Restricted Access Vehicles

11. • PBS is an alternative regulatory scheme for heavy vehicles
that was developed throughout the 2000s in order to meet
the demands of the growing road freight task and allow more
widespread adoption of higher productivity vehicles.
• It was initially trialed by jurisdictions and subsequently
formally adopted by the National Transport Commission (NTC)
in a regulatory sense in 2011.
• The standard seeks to achieve:
– a more sustainable transport system through improved road
vehicle regulations
– a more flexible road transport regulatory environment that
allows for greater innovation in vehicle design
Performance Based Standard
11

12. C. Treatment of high-productivity
vehicles in Queensland
12
• Department of Transport and Main Roads publishes a set of maps
via their website (same for all other States)
• Direct translation between the existing Restricted Vehicle Access
conditions and roads classified under PBS.

13. • To begin with, the applicant needs to consult with the
relevant road authorities to discuss the likelihood of being
granted road network access
• Only accredited PBS assessors can submit PBS Design
applications to the NHVR. Includes investigation of road
network access to design development stage.
• Onus is on the applicant to prove suitability of the proposed
vehicle design as well as the associated vehicle mass, bridge
loadings and the level of PBS network compliance.
• Funding of infrastructure improvements by PBS applicant is
considered on a case by case basis.
• Only after PBS vehicle approval can applicant apply for a
permit with the NHVR.
PBS Road Access Application
13

14. PBS Class B categories provide for longer than current general
access, B-double, Type 1 and Type 2 road train combinations.
This means:
• Longer storage lane lengths at intersections;
• Longer signal timing for left or right turns at intersections;
• Increased overtaking provisions on rural roads;
• Increased enforcement bays and rest area sizes;
• More stacking distance at railway level crossings;
• Larger radius swept paths and median openings
• Greater impact on last mile constraints.
PBS Class B network
14

15. 15
• The B double is currently Australia’s safest and most efficient
mainstream heavy freight vehicle.
• Reasons include
– Better driver education
– safer performance of larger vehicles
– increased levels of enforcement
– Greater participation in the Intelligent Access Program (IAP)
D. Understanding the impact of these
larger vehicles on our roads

16. • Less heavy vehicles on
our roads
• More efficient movement
of freight
• Increased payload
capacities, especially for
minerals and grain
16
• Intersection geometry
• Pavement loading
• Bridge loading
• Road width requirements
• Actual road wear
PRO’s CON’s
So why all the fuss ?

17. Intersection geometry
17
• Low speed swept path impact on existing intersections most
common shortcoming.
• Mitigation includes:
– Pavement widening
– Additional line marking / painted islands
– Roadside furniture set back

18. Pavement loading (1/2)
18
Maximum mass (tonnes)
permitted under GML
Maximum mass (tonnes)
permitted under HML
Single drive axles on buses 9.0 t 10.0 t
Six-tyred tandem axle groups 13.0 t 14.0 t
Tandem axle group 16.5 t 17.0 t
Tri-axle group 20.0 t 22.5 t

19. Pavement loading (2/2)
19

20. Bridge loading
20
• Bridges also need to withstand the amplified effects of
dynamic loading, over-loading, vertical and horizontal shock
forces such as in areas where heavy vehicle braking occurs.
• From a structural perspective, heavier payloads do not
necessarily relate to greater relative bridge impacts.
• This is because in some instances the longer vehicle types are
able to spread their axle loads more evenly across the
structure or even bridge a short span length.

21. Road width requirements
21
• This measure considers the vehicle’s ability to remain within
the available traffic lane width along a straight road.
• This measure is influenced by variations in the road surface
due to cross-fall, unevenness and localised failures on
occasion.
• Mitigation:
– increase the available lane width or
– construct a surfaced shoulder

22. Recent Survey Results
22
• Consistent with
previous studies
• Main findings relate
to:
– road lane width
and
– road surface
condition
• As perceived by the
motoring public
(as opposed to
engineers)

23. Actual road wear
23

24. E. How should traffic engineers
and planners respond
24
• Road Controlling Authorities and Councils are under severe
pressure to maintain the condition of our roads. This effort may
be diverting funding away from other areas of greater need.
• The advent of larger vehicles have the potential change many of
our previous assumptions about vehicle performance and how
they impact on our roads.
• More needs to be done towards encouraging the use of the
right size of vehicle for the right size of job, especially if there a
viable parallel alternative available, such as rail.
• Bigger trucks might be more efficient, but they are also having
an impact on the behaviour of other drivers and the perceived
level of safety associated with the driving task when combined
with other smaller vehicle types.

25. Banora Point Upgrade, New South Wales, Australia
Thank you
DERRICK HITCHINS National Sector Leader Traffic
and Transport Planning, SMEC Australia Pty Ltd
derrick.hitchins@smec.com
ADAM RITZINGER
Senior Engineer, Advantia Transport Consulting Pty Ltd
adam@advantia.com.au